This invention relates to a cutter tool having removable teeth. The employment of removable teeth for cutters is known in the prior art as represented by the following United States Patents:
______________________________________ PATENT NO. INVENTOR TITLE ______________________________________ 3,564,946 Kaser Core Borer 4,230,429 Eckle Boring Tool For Making Borings in Solid Metal Material Of Workpieces 4,442,812 Linville Rotatable Shell Cutter 4,500,234 Orth et al Trepanning Tool 4,595,320 Berner et al Boring Tool With A Double Cutter Head, In Which The Working Load Is Prevented Outside The Elastic Range Of The Cutting Bit Holder Material In The Vicinity Of The Outermost Radial Positioning 4,616,965 Anderson et al Indexable Shell Cutter 4,679,968 Tsuiimura et al Indexable Cutter Insert 4,968,192 Hamilton Trepanning Tool 5,049,011 Bohnet et al Rotary Boring Tool With Indexable Cutter Chips 5,092,718 Shallenberger Drill With Replaceable Cutting Inserts 5,188,490 Muendlein et al Tool With Adjustable Interchangeable Cartridge 5,269,618 Meyer Indexable Insert Drill ______________________________________
Having replaceable teeth for a cutting tool has many obvious advantages, the primary one being economy. The useful life of a cutting tool is usually determined by the cutting ability of the teeth. When the teeth wear and lose their ability to cut, they can, in some instances, be sharpened in place. However, after repeated sharpening sufficient material may be removed from the teeth that they no longer can perform a cutting function or the teeth may become chipped or broken. A cutting tool having fixed teeth that are beyond sharpening or become broken must be discarded which means discarding the cutter blade that supports the teeth even though the cutter blade itself may otherwise be useable.
An additional advantage of removable teeth is that it is normally easier to sharpen or refinish teeth when they are not a part of a cutter blade. A major advantage, however, of replaceable teeth, is that when teeth become unusable, either because of wear or they are broken or chipped, it is much less expensive to replace one or more teeth in a cutter tool than to discard the entire cutter tool.
A problem that exists with replaceable teeth cutters is that of retaining removable teeth in position in the cutter blade. Cutter tools are frequently used in applications that exert extreme forces on the teeth. For instance, when a cutter tool is used to cut a hole in a steel pipe by means of a circular cutter head the forces on the teeth can be enormous. In addition, substantial vibration may occur between the cutter tool and the work piece. Another example of adverse cutting conditions is the use of a cutter tool to cut non-metallic workpieces, such as granite, concrete, or the like. Obviously, if a tooth becomes loosened in the cutter tool the cutter tool can be destroyed or the workpiece may be damaged. Because of the problem of retaining removable teeth in cutter tools, the use of cutter tools having removable teeth has not been universally employed irrespective of the advantages that otherwise exist for removable teeth cutter tools.